Underground bike lanes.

San Sebastian inaugurated the world's longest bicycle commuter tunnel in 2009. Basically its a converted train tunnel. 

but it looks quite cool and makes you wonder what it would be like to be able to cycle for long (ish) distances in the dry at speed ( not intersections ) and in the cool ( good for spain)  

This link http://www.diariovasco.com/videos/gipuzkoa/actualidad-de-gipuzkoa/690890454001-tunel-morlans-amara-ibaeta-bicicleta.html

lets you see a spanish TV report. Looks quite nice - I'd love to try it out. 

Naturally digging a tunnel is the most expensive way of getting road space but if its available then why not use it. Does make you wonder about the carrying capacity of this tunnel with bikes vs the same thing with trains. 

Sustrans talk about one in the UK - another abandoned Rail system. 

http://www.sustrans.org.uk/what-we-do/connect2/schemes/south-west/bath-two-tunnels?id=2

the wireroad

I found this cycle monotrails system and I'm very very intrigued by it.  This looks to be partly thin  ( I mean thin) rail and partly steel wire but for the life of me I can't quite see how it works. Have a look and for your self.



If it was possible (which it clearly is)  to have sections of wire cable for a monorail that that would be a truly remarkable thing. The visual intrusion argument would be over. I've been looking at the video again and again and I think this system works mostly on a rail ( like the Wuppertal Schwebebahn) monorails and then has a stretch of cable pulled between two solid rails which extend on to it.


Which is exactly what you need. - the solid rail for curved sections and the wire sections for straight  places where you need very very minimal visual intrusion. The wire here is even smaller than the sheweb enclosed . So basically you have an aerial tramway (aka cable car / ski lift) - which has a good history behind it of operation with sections of tracked monorail.

Naturally being a cycle system you get very thin wires with amount as minimal intrusion as you could expect.

More sweeb

A nice more detailed vid about the Sweeb system.